1. Field of the Invention
The invention relates to alcohol alkoxylates and mixtures thereof which can be used as low-foam or foam-suppressing surfactants, for example in detergents and cleaners and in formulations for chemicotechnological applications, and to detergents and cleaners comprising them.
2. Description of the Background
Low-foam or foam-suppressing surfactants from ethoxylated and propoxylated alcohols are known per se. U.S. Pat. No. 5,766,371 relates to biodegradable low-foam surfactants which can be used as rinse aids in dishwashing detergents. It describes C4-18-alkanols reacted firstly with propylene oxide and then with ethylene oxide and finally with a C4-8-alkylene oxide.
U.S. Pat. No. 5,294,365 relates to hydroxypolyethers which can be used as low-foam surfactants. Here, C1-18-alcohols are firstly reacted with ethylene oxide, then with propylene oxide and then with glycidyl ethers.
U.S. Pat. No. 4,827,028 relates to anionic surfactants obtained by reacting C1-8-alcohols with ethylene oxide, then propylene oxide and then an alkylene oxide having at least 8 carbon atoms. The order of the reaction with propylene oxide and ethylene oxide can also be reversed.
WO 96/12001 relates to biodegradable surfactants which can be used as rinse aids. The surfactants are predominantly obtained by reacting C4-18-alcohols with propylene oxide, then ethylene oxide and then C4-18-alkylene oxides. The examples also describe the reaction of C6-10-alcohols with at least 20 mol of ethylene oxide and then butylene oxide or decylene oxide.
The known low-foam surfactants do not have a suitable combination of properties of foam suppression, wetting action and ability to be formulated which is suitable for all applications.
The known surfactants sometimes also have a relatively high ecotoxicological hazard potential, in particular toward aquatic organisms.
It is an object of the present invention, therefore, to provide alcohol alkoxylates which have an improved spectrum of properties and can, in particular, be used as low-foam and foam-suppressing surfactants. They should be suitable, in particular, for use in detergents and cleaners and for chemicotechnological applications.
We have found that this object is achieved according to the invention by alcohol alkoxylates of the formula (I)
R1xe2x80x94Oxe2x80x94(CH2xe2x80x94CHR5xe2x80x94Oxe2x80x94)r(CH2xe2x80x94CH2xe2x80x94Oxe2x80x94)n(CH2xe2x80x94CHR6xe2x80x94Oxe2x80x94)s(CH2xe2x80x94CHR2xe2x80x94Oxe2x80x94)mHxe2x80x83xe2x80x83(I) 
where
R1 is an at least singly branched C4-22-alkyl
R2 is C3-4-alkyl
R5 is C1-4-alkyl
R6 is methyl or ethyl
n is an average value from 1 to 50
m is an average value from 0 to 20, preferably 0.5 to 20
r is an average value from 0 to 50
s is an average value from 0 to 50,
where m is at least 0.5 if R5 is methyl or ethyl or r is 0.
The object is also achieved according to the invention by a mixture comprising 20 to 95% by weight, preferably 30 to 95% by weight, of at least one of the above alcohol alkoxylates and 5 to 80% by weight, preferably 5 to 70% by weight, of a corresponding alcohol alkoxylate but in which R1 is an unbranched alkyl radical with the same number of carbon atoms.
The object is also achieved by alcohol alkoxylates of the formula (II)
R3xe2x80x94(CH2xe2x80x94CH2xe2x80x94Oxe2x80x94)p(CH2xe2x80x94CHR4xe2x80x94)qHxe2x80x83xe2x80x83(II) 
where
R3 is branched or unbranched C4-22-alkyl
R4 is C3-4-alkyl
p is an average value of from 1 to 50, preferably 4 to 15
q is an average value of from 0.5 to 20, preferably 0.5 to 4, more preferably 0.5 to 2.
The object is also achieved by mixtures comprising 5 to 95% by weight of at least one branched alcohol alkoxylate (II), as described immediately above, and 5 to 95% by weight of a corresponding alcohol alkoxylate but in which an unbranched alkyl radical is present instead of a branched alkyl radical.
In the alcohol alkoxylates of the formula (I), R2 is preferably propyl, in particular n-propyl.
In the alcohol alkoxylates of the formula (I), n preferably has an average value of from 4 to 15, particularly preferably 6 to 12, in particular 7 to 10.
m preferably has an average value of from 0.5 to 4, particularly preferably 0.5 to 2, in particular 1 to 2. The expression xe2x80x9caverage valuexe2x80x9d refers to technical-grade products in which differing numbers of alkylene oxide units may be present in the individual molecules. It describes the proportion of corresponding alkylene oxide units which are on average present in technical-grade products. A value of 0.5 therefore means that, on average, every second molecule carries a corresponding unit. Instead of the lower limit of 0.5, according to a preferred embodiment of the invention, the lower limit for the indices n, m, p and q is 1.
r is preferably 0. s is preferably 0.
The radical R1 is preferably a C8-15xe2x80x94, particularly preferably a C8-13xe2x80x94, in particular a C8-12-alkyl radical which is at least singly branched. Two or more branches may also be present.
R5 is preferably methyl or ethyl, in particular methyl.
R6 is preferably ethyl.
The mixtures contain compounds with unbranched and with branched alcohol radicals R1. This is the case, for example, in the case of oxo alcohols which have a proportion of linear alcohol chains and a proportion of branched alcohol chains. For example, a C13/15-oxo alcohol frequently has about 60% by weight of completely linear alcohol chains, but in addition also about 40% by weight of xcex1-methyl-branched and Cxe2x89xa72-branched alcohol chains.
In the alcohol alkoxylates of the formula (II), R3 is preferably a branched or unbranched C8-5-alkyl radical, particularly preferably a branched or unbranched C8-13-alkyl radical and in particular a branched or unbranched C8-12-alkyl radical.
R4 is preferably propyl, in particular n-propyl. p preferably has an average value of from 4 to 15, particularly preferably an average value of from 6 to 12 and in particular an average value of from 7 to 10. q preferably has an average value of from 0.5 to 4, particularly preferably 0.5 to 2, in particular 1 to 2.
Analogously to the alcohol alkoxylates of the formula (I), the alcohol alkoxylates of the formula (II) can also be present as mixtures containing unbranched and branched alcohol radicals.
Suitable alcohol components on which the alcohol alkoxylates according to the invention are based are not only pure alkanols, but also homologous mixtures with a range of carbon atoms. Examples are C8/10-alkanols, C10/12-alkanols, C13/15-alkanols, C12/15-alkanols. Mixtures of two or more alkanols are also possible.
The above alkanol alkoxylates or mixtures according to the invention are preferably prepared by reacting alcohols of the formula R1xe2x80x94OH or R3xe2x80x94OH or mixtures of corresponding branched and unbranched alcohols optionally firstly with C3-6-alkylene oxide, then with ethylene oxide and subsequently optionally with C3-4-alkylene oxide and then a corresponding C5-6-alkylene oxide. The alkoxylations here are preferably carried out in the presence of alkoxylation catalysts. Use is made here in particular of basic catalysts, such as potassium hydroxide. Using special alkoxylation catalysts, such as modified bentonites or hydrotalcites, as are described, for example, in WO 95/04024, the random distribution of the amounts of incorporated alkylene oxides can be severely restricted, giving xe2x80x9cnarrow-rangexe2x80x9d alkoxylates. As a result, the random distribution of the amount of alkylene oxide units in technical-grade mixtures can be severely restricted.
The alcohol alkoxylates or mixtures thereof according to the invention are preferably used in accordance with the invention as low-foam or foam-suppressing surfactants.
The low-foam or foam-suppressing surfactants according to the invention can be used in a large number of applications. They are preferably used as nonionic surfactants, preferably in detergent and cleaner formulations and in surfactant-containing formulations for chemicotechnological applications, for example for industrial and domestic cleaning processes, and for textile washing or for cleaning processes in the food sector, such as the cleaning of beverage bottles or of containers or equipment in the food-processing industry or in dishwashing detergents. In particular, the cleaning of hard surfaces made of, for example, glass, ceramic, surface coating, plastic or metal is of interest here. The surfactants are also used in industrial cleaners and in cleaning processes in the metal-processing industry.
The surfactants can also advantageously be used for a large number of other chemicotechnological processes, thus generally in the metal-processing industry, for example in
cooling lubricants,
hardening oils,
hydraulic oil emulsions,
polishing pastes,
mold release agents,
drawing oils,
mordants,
metal cleaners,
metal dryers.
In this connection, surfactants may be used advantageously specifically in processes in which high thermal stability is of importance.
The surfactants can also be used in the manufacture and processing of textiles. The use of surfactants during the manufacture and processing of textiles is extremely multifaceted, extending predominantly to the areas
pretreatment agents of fibers,
preparation of rayon fibers,
spin finishers and textile lubricants,
dyeing auxiliaries,
hand modifiers,
hydrophobicization agents,
auxiliaries for printing,
antistats,
flocculants and coatings.
Surfactants can also be used in the leather, paper, printing, electroplating and photographic industry. Important application fields here are surface coatings, pigments and printing inks. Surfactants are used in these application fields both in aqueous and in nonaqueous systems. In nonaqueous systems, they serve primarily as dispersion auxiliaries, antisettling agents or flow-control agents. In addition, surfactants permit the preparation of so-called high-solids systems. Surfactants have a greater proportion in aqueous systems in which they are used not only for the stabilization of the polymer-dispersion-based binders prepared by emulsion polymerization or polycondensation, but also as dispersion auxiliaries of often used organic or inorganic pigments. In addition, they improve the adhesion properties of these coating materials.
In addition, the surfactants can be used in water treatment, for example in wastewater purification.
The surfactants can also be used in crop-protection formulations.
The compounds can also be used as surfactants or emulsifiers in the polymer-production and polymer-processing industry. The main fields of use in the production and processing of polymers are
preparation of polymer dispersions,
preparation of bead polymers,
preparation of foams,
use of surface-active mold release agents,
preparation of microcapsules,
improvement of the adhesion between fillers and plastics,
additives to polymer dispersions for achieving particular effects, such as foamability, filler compatibility or wetting ability,
emulsifiers for nonaqueous systems,
coloring plastics,
antistatic finishing of plastics,
adhesives.
The present invention likewise provides detergent and cleaner formulations which (in addition to the customary constituents) comprise, as surfactants, 0.1 to 40% by weight, in particular 1 to 30% by weight, especially 10 to 25% by weight, based on the total amount of the formulation, of at least one compound of the formula (I) or (II) according to the invention. In addition, these formulations can also comprise further nonionic surfactants, but also cationic, anionic and/or amphoteric surfactants. The customary constituents of detergent and cleaner formulations are known to the person skilled in the art.
The alkoxylates described in most cases display an unusually low interfacial tension, especially with respect to nonpolar oils such as engine oils (of importance for use in industrial cleaners), which correlates very highly with a high fat-dissolving power, is effective in reducing the surface tension and results in a very low critical micelle concentration. They usually exhibit very good wetting power on hard surfaces and very good wetting power on textile surfaces. In the wash they mostly produce little foam, which makes them suitable for textile detergents, in particular powder detergents. Even in machine and manual cleaning processes they generally produce only little foam, in most cases have a foam-suppressing action and in most cases effect rapid foam disintegration.
The alkoxylates described are readily biodegradable and largely toxicologically safe, in particular their aquatic toxicity is significantly lower than that of comparable commercial products.
The invention is illustrated in more detail by the examples below.